• 한국압력기기공학회 논문집
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• 제15권2호
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• pp.1-8
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• 2019

The integrity of the Reactor Pressure Vessel (RPV) is affected by the neutrons bombarding the vessel wall leading to embrittlement. This irradiation-induced embrittlement leads to reduction in the fracture toughness of RPV materials. This paper presents a comparative study of typical Optimized Power Reactor (OPR)1000 reactor pressure-temperature (P-T) limit curves using the pre-2006 American Society of Mechanical Engineers (ASME) editions used in the power plant and the current ASME edition of 2010. The current ASME Code utilizes critical reference stress intensity factor based on the lower bound of static, while the Pre-2006 ASME editions are based the critical reference stress intensity factor based on the lower bound of static, dynamic and crack arrest. Model-Based Systems Engineering approach was used to evaluate ASME Code Section XI Appendix G for generating the P-T limit curves. The results obtained from this analysis indicate decrease in conservatism in P-T limit curves constructed using the current 2017 ASME code, which can potentially increase operational flexibility and plant safety. Hence it is recommended to use ASME code edition after 2006 be used in all operating nuclear power plants (NPPs) to establish P-T limit curve.

• Journal of Advanced Marine Engineering and Technology
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• 제25권2호
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• pp.351-356
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• 2001

In this paper, a general one-loop control system was assumed as a model system which has a time-delay element connected with a first order-lag element in series. After the corresponding parameter set causing stability limit condition for the model system was obtained by mathematical procedures, their loci on the parameter space was taken according of frequency change,. The parameter set loci of stability limit showed a specific pattern, and particularly the curves on the Kp-Ti parameter space were able to generalized in the form of an exponential formula. These properties were also compared with the results taken from experimental procedures by Nyquist response method and Ziegler & Nichols method on the time domain, and both results were confirmed to be nearly same.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.12-15
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• 2002

In this study, we will try to develop the 3D automatic design program of limit gauge. When users, who Have some mechanical information input some date, they can do 3D-modeling easily like expert. This is one of the merit in automatic design program and the automatic design program can compare the limit gauge made in this study with processed the bolt and nut model. This demonstrates the effective value of automatic design model. Limits gauge of sort divide into ring gauge of measuring bolt and pin gauge of measuring nut. The new automatic design program follows the KS

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.604-607
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• 2002

In this study, we will try to develop the 3D automatic design program of limit gauge. When users, who have some mechanical information, input some date, they can do 3D-modeling easily like expert. This is one of the merit in automatic design program and the automatic design program can compare the limit gauge made in this study with processed the bolt and nut model. This demonstrates the effective value of automatic design model. Limits gauge of sort divide into ring gauge of measuring bolt and pin gauge of measuring nut. The new automatic design program follows the KS.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 추계학술대회 논문집(Proceeding of the KOSME 2000 Autumn Annual Meeting)
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• pp.135-142
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• 2000

The adjusting parameter set which enable control systems to locate on stability limit can be derived from theoretical or trial methods for an existing real system. The data from the results are much available to keep a system in the Proper stability condition even to site engineers who are inexperienced in the control system. In this paper, a general one loop control system was adopted for a model system the process of which was assumed to consist of a time-delay element and a first order-lag element in series. After obtaining the corresponding parameter set for the model system by mathematical procedures, their loci on the parameter space was taken according to frequency change. The parameter set loci of stability limit showed unique pattern, and particularity , the curves on the Kg-Ti parameter space were able to be generalized in the form of, an unique exponential formula. These properties were also compared with the results taken from experimental procedures by Nyquist response method and Ziegler & Nichols method on the time domain, and both results were confirmed to be nearly same.

• 대한수학회논문집
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• 제20권3호
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• pp.579-588
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• 2005

In this paper we study the asymptotics for the energy density in the self-dual Chern-Simons CP(1) model. When the sequence of corresponding multivortex solutions converges to the topological limit, we show that the field configurations saturating the energy bound converges to the limit function. Also, we show that the energy density tends to be concentrated at the vortices and antivortices as the Chern-Simons coupling constant $\kappa$ goes to zero.

• Journal of the Korean Statistical Society
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• 제36권2호
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• pp.183-200
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• 2007

We consider a nonlinear autoregressive moving average model with nonlinear GARCH errors, and find sufficient conditions for the existence of a strictly stationary solution of three related time series equations. We also consider a geometric ergodicity and functional central limit theorem for a nonlinear autoregressive model with nonlinear ARCH errors. The given model includes broad classes of nonlinear models. New results are obtained, and known results are shown to emerge as special cases.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 가을 학술발표회 논문집
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• pp.35-42
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• 1995

One of the main objectives of this study is to propose a realistic limit state model for reliability-based safety assessment of precast segmental prestressed concrete box girder bridges, considering 1) combined effects of bending, shear and torsional forces, and 2) the difference between transverse reinforcments of box girder. A improved limit state model is derived from a modified interaction equation compared with the Bruno's equation. A Drectional sampling algorithm is used for reliability analysis of the proposed model.

• 대한수학회보
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• 제61권2호
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• pp.479-488
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• 2024

Convergence to a steady state in the long term limit is established for global weak solutions to a chemotaxis model with degenerate local sensing and consumption, when the motility function is C¹-smooth on [0, ∞), vanishes at zero, and is positive on (0, ∞). A condition excluding that the large time limit is spatially homogeneous is also provided. These results extend previous ones derived for motility functions vanishing algebraically at zero and rely on a completely different approach.

• 한국세라믹학회지
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• 제28권11호
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• pp.878-884
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• 1991

The mobility and diffusivity in an edge dislocation in an FCC crystal formed by the removal of one half of a (100) plane were evaluated in an applied field by analyzing a vacancy tight binding model using Stark's matrix technique. A model of an edge dislocation in an FCC crystal was constructed for a [100] Burgers vector where vacancy transport along the edge dislocation in an FCC crystal was constructed for a [100] Burgers vector where vacancy transport along the edge of the extrac half plane of ions was considered. The model considered a tight binding approximation of the vacancy to the compressed region of the core and carried the calculation to the limit of an infinite length of dislocation. The diffusivity and the ratio of mobility to diffusivity were found to increase without bounds in the limit where the correlation factor becomes zero. In contrast, as the correlation factor became unity, the diffusivity became zero and the ratio of mobility to diffusivity became unity associated with the uncorrelated limit of 1/kT. This implied that the phenomenon was not unique to the crystal structure but was unique to edge dislocations with vacancy tight binding.